Effects of Fiber Length on Elastic Moduli of Randomly-Oriented Chopped-Fiber Composites

G. J. Weng, C. T. Sun

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

; Based on a composite-cylinder model with a short cylindrical fiber embedded in the center of a cylindrical matrix, the longitudinal Young's modulus and major Poisson's ratio of a unidirectional, short-fiber composite are found in terms of the fiber volume fraction and the tip-to-tip spacing of the fibers. The expressions obtained are then modified to account for the influence of volume fraction and aspect ratio of the fibers. These results, together with Christensen and Waals' normalized expressions, are used to calculate the Young's modulus and Poisson's ratio of a randomly-oriented chopped-fiber composite in terms of the fiber volume fraction and its aspect ratio. The theory developed is then applied to examine numerically the eifects of fiber length on the Young's modulus and Poisson's ratio of short glass-fiber/polyester-resin composites. The results show that the Young's modulus of both unidirectional and randomly-oriented fiber composites are strongly dependent on the fiber length; so is the Poisson's ratio, though to a lesser degree.

Original languageAmerican English
Title of host publicationComposite Materials
Subtitle of host publicationTesting and Design (Fifth Conference)
EditorsS. W. Tsai
PublisherASTM International
Pages149-162
Number of pages14
ISBN (Electronic)0803144954, 9780803144958
DOIs
StatePublished - 1979
Event5th Conference on Composite Materials: Testing and Design - New Orleans, United States
Duration: Mar 20 1978Mar 22 1978

Publication series

NameASTM Special Technical Publication
VolumeSTP 674

Conference

Conference5th Conference on Composite Materials: Testing and Design
Country/TerritoryUnited States
CityNew Orleans
Period3/20/783/22/78

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)

Keywords

  • composite materials
  • fiber aspect ratio
  • modulus of elasticity
  • randomly-oriented chopped-fiber composite
  • unidirectionally-aligned discontinuous-fiber composite

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